Tudor Tămaș

An unusual blue-purple shell coloration was observed in specimens of Rapana venosa collected as discarded biogenic carbonate along the Romanian Black Sea coast. This chromatic feature has not previously been reported for this species, which is typically characterized by a grey-brown exterior and bright orange-pink aperture. Despite the ecological and economic relevance of this veined rapa whelk, the chemical nature of its shell pigments remains poorly understood. Here, we present a comprehensive molecular and structural characterization of the pigments responsible for this atypical coloration.,Resonance and non-resonance Raman microspectroscopy with multiple excitation wavelengths were employed, complemented by surface-enhanced Raman scattering (SERS), Fourier-transform infrared spectroscopy (FT-IR), powdered X-ray diffraction (XRD), and SEM-EDX analysis. Raman analyses revealed the coexistence of aragonite and calcite with a clear cross-sectional gradient, aragonite being enriched in the inner shell layers and calcite towards the exterior. Pigment distribution was strongly excitation-wavelength dependent. Spectroscopic data excluded indigotin derivatives and caroteno-protein complexes as major chromophores responsible for the blue colouration. Instead, the coloration arises from a complex mixture of endogenous methylated polyenes with different conjugation lengths, including species with partial triple-bond character, embedded within the mineral-organic matrix. These polyenes coexist and interact with melanins and porphyrin-type compounds, producing the observed blue-purple hue. SERS analysis of ethanol extracts identified β-carotene at sub-micromolar levels as the only solvent-extractable carotenoid, confirming that the dominant polyenes are non-extractable and structurally bound within the shell framework.,This study reveals a previously unrecognized polyene-based pigment system in Rapana venosa shells and demonstrates how pigment-biomineral interactions and molecular conjugation length contribute to shell coloration, providing new insights into the naturally occurring polyenic chromophores in biomineralized tissues.

Objectives: Febuxostat (FEB) is a poorly soluble xanthine oxidase inhibitor, which limits its in vitro dissolution performance. This study aimed to enhance the aqueous solubility and dissolution behavior of FEB through crystal engineering (salt and co-crystal formation) and the development of PEG6000-based amorphous solid dispersions. Methods: Three FEB salts with p-toluenesulfonic acid (Tos1), tromethamine, and N-methyl-D-glucamine, as well as one FEB co-crystal with acridine (Acd1), were prepared together with their amorphous solid dispersions using PEG6000. Solubility, dissolution, and physical stability were evaluated in water and biorelevant media (FaSSIF). Cytotoxicity was assessed in HepG2 cells, while antioxidant and anti-inflammatory activities were investigated in monosodium urate–stimulated macrophages. Key findings: Salt formation significantly improved FEB solubility, with Tos1 increasing solubility from 27 ± 2 μg/ml (FEB) to 100 ± 2 μg/ml in water and from 316 ± 2 μg/ml to 364 ± 2 μg/ml in FaSSIF. Incorporation into PEG6000 further enhanced Tos1 solubility to 134 ± 2 μg/ml in water and 481 ± 2 μg/ml in FaSSIF. In contrast, the Acd1 co-crystal showed limited solubility in water but exhibited slower dissolution, suggesting suitability for sustained-release applications. None of the novel formulations increased cytotoxicity. Tos1 and its PEG6000 dispersion maintained the highest HepG2 cell viability and significantly reduced malondialdehyde levels and intracellular uric acid in macrophages. Conclusions: The combined application of crystal engineering and PEG6000-based amorphous solid dispersions selectively enhances the solubility, dissolution, and in vitro biological performance of febuxostat. This strategy offers a rational approach for optimizing FEB formulations and addressing the limitations associated with poorly soluble drugs.

Seafood-derived carbonate waste, primarily calcium carbonate (CaCO₃), has attracted growing interest for sustainable reuse, yet the unique potential of aged biogenic sources remains underexplored. Blue crab (Callinectes sapidus) shells are particularly distinctive: they consist of Mg-calcite with an intrinsic 3D-porous structure and naturally embedded astaxanthin, a potent antioxidant not found in other calcite- or aragonite-based residues. While organic degradation over time is often assumed to compromise functionality, this study demonstrates that five-years-aged crustacean shell waste retains both its crystallinity and bioactive carotenoids after calibrated ball milling. Across four powder batches produced under distinct milling conditions by varying frequencies and durations, dynamic light scattering confirmed only subtle particle size variation, while Raman spectroscopy, XRD, FT-IR, and SEM-EDX confirmed structural and chemical integrity and highlighted the subtle amorphization induced by slightly different milling parameters, which, in turn, driven to slightly different conversion efficiency into phosphate mineral. Strikingly, all powders underwent rapid transformation into dicalcium phosphate dihydrate (brushite) enriched with carotenoids upon reaction with phosphoric acid. This work reveals, for the first time, that years-aged biogenic Mg-calcite waste not only preserves its naturally embedded carotenoids but also offers a direct route to functional phosphate composites, establishing its untapped value in environmental and biomedical applications.

The sustainable conversion of biogenic waste into high-value materials presents a promising approach for addressing environmental and industrial challenges. This work reports an advancement into antioxidant-enriched phosphate minerals derived from green conversion of biogenic calcium carbonates of crustaceans. We demonstrate the effectiveness of Raman technology in controlling conversion using phosphoric acid treatment. The effects of reaction parameters—including acid stoichiometry, granular size distribution, and thermal treatment at 700 °C and 1200 °C—were systematically evaluated. Raman spectroscopy results validated by X-ray diffraction (XRD) and SEM-EDX analyses revealed mixed-phase minerals monetite, brushite, whitlockite or hydroxylapatite, respectively. Notably, reducing particle size enhanced conversion efficiency by increasing the reactive surface area, while the use of excess phosphoric acid facilitated conversion to monocalcium phosphate and promoted the degradation of the organic matrix. Thermal treatment further altered the product composition: heating at 700 °C produced a whitlockite-rich phase, whereas treatment at 1200 °C shifted the balance toward hydroxylapatite. The synthesized calcium phosphate compounds, including hydroxylapatite, monocalcium phosphate, whitlockite, and brushite, hold significant practical utility in biomedical applications (such as bone grafts and dental implants), agriculture, and industrial processing. Moreover, we have proven that by controlling the reaction parameters the final product composition can be tailored according to the specific needs. A greener approach yields brushite, monetite, or monocalcium phosphate, while a more energy-demanding process, including heating to 1200 °C, yields a high-purity hydroxylapatite. This research offers a sustainable analytical route for producing high-purity calcium phosphate materials from wasted biomaterials, contributing to both the bioeconomy as well as scientific innovation.

This pilot study uses Raman spectroscopy and SERS to monitor monthly water composition changes in two adjacent hypersaline lakes (L1 and L2) at a balneary resort, during the peak tourist season (May–October 2023). In situ pH and electrical conductivity (EC) measurements, along with evaporite analyses, complemented the spectroscopic data. Although traditionally considered similar, the lakes frequently raise public questions about their relative bathing benefits. While not directly addressing the therapeutic effects, the study reveals distinct physicochemical profiles between the lakes. Raman data showed consistently higher sulfate levels in L2, a trend also observed in winter monitoring. pH levels were higher in L1 (8–9.8) than in L2 (7.2–8), except for one October depth reading. This trend held during winter, except in April. Surface waters showed more variability and slightly higher values than those at 1 m depth. SERS spectra featured β-carotene peaks, linked to cyanobacteria, and Ag–Cl bands, indicating nanoparticle aggregation from inorganic ions. SERS intensity strongly correlated with pH and EC, especially in L2 (r = 0.96), suggesting stable surface–depth chemistry. L1 exhibited more monthly variability, likely due to differing biological activity. Although salinity and EC were not linearly correlated at high salt levels, both reflected seasonal trends. The integration of Raman, SERS, and physicochemical data proves effective for monitoring hypersaline lake dynamics, offering a valuable tool for environmental surveillance and therapeutic water quality assessment, in support of evidence-based water management and therapeutic use of salt lakes, aligning with goals for sustainable medical tourism and environmental stewardship.

Biogenic carbonate waste from seafood exploitation, primarily composed of calcium carbonate (CaCO₃), occurs in various polymorphic forms, making it valuable for envi-ronmental and biomedical applications. Mg-calcite from blue crab (Callinectes sapidus) shells is especially promising due to its 3D-ordered porosity and naturally embedded astaxanthin antioxidant, offering advantages over other calcite- or aragonite-based waste. These properties enable its use in pharmaceutical formulations and biostimulants for ac-tive compound loading and controlled release. However, long-term aged biogenic waste may experience organic degradation, potentially altering its physical, chemical, and functional performance. In this study, calibrated ball milling conditions were applied to years-aged biogenic waste to assess structural integrity, crystallinity, and functionality of the resulting powders. Notably, the antioxidant carotenoid remained preserved across all fine powders. Dynamic light scattering revealed that particle size distribution varied subtly between two milling durations (12 and 15 min) and frequencies (25 and 27 Hz). Pigmentation, crystallinity, and repurposing potential of the powders were investigated using Raman spectroscopy, X-ray diffraction (XRD), FT-IR, and SEM-EDX. Ultimately, all four powder batches showed successful conversion into phosphate minerals enriched with antioxidants when treated with phosphoric acid, highlighting the potential of aged shell waste in high-value applications under optimized mechanical and chemical condi-tions.

The sustainable conversion of biogenic waste into high-value materials presents a promising approach for addressing environmental and industrial challenges. This work reports an advancement into antioxidant-enriched phosphate minerals derived from green conversion of biogenic calcium carbonates of crustaceans. We demonstrate the effectiveness of Raman technology in controlling conversion using phosphoric acid treatment. The effects of reaction parameters—including acid stoichiometry, granular size distribution, and thermal treatment at 700 °C and 1200 °C—were systematically evaluated. Raman spectroscopy results validated by X-ray diffraction (XRD) and SEM-EDX analyses revealed mixed-phase minerals monetite, brushite, whitlockite or hydroxylapatite resepectively. Notably, reducing particle size enhanced conversion efficiency by increasing the reactive surface area, while the use of excess phosphoric acid facilitated conversion to monocalcium phosphate and promoted the degradation of the organic matrix. Thermal treatment further altered the product composition: heating at 700 °C produced a whitlockite-rich phase, whereas treatment at 1200 °C shifted the balance toward hydroxylapatite. The synthesized calcium phosphate compounds, including hydroxylapatite, monocalcium phosphate, whitlockite, and brushite hold significant practical utility in biomedical applications (such as bone grafts and dental implants), agriculture, and industrial processing. Moreover, we have proven that by controlling the reaction parameters the final product composition can be tailored according to the specific needs, a greener approach yields brushite, monetite, or monocalcium phosphate while a more energy demanding process including heating to 1200 0C yields a high purity hydroxylapatite. This research offers a sustainable analytical route for producing high-purity calcium phosphate materials from wasted biomaterials, contributing to both bioeconomy as well as scientific innovation.

The microfacies analysis and mineralogical investigations (X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy) of a four-meter sedimentary succession in the Cave from Izvorul Tăușoarelor (Rodnei Mountains) provided new insights into paleontological and paleoenvironmental features of a ramp-type depositional system during the late Eocene. The studied succession consists of rhythmic alternations of limestone, carbonate micro-breccia, sandstone, and a thin clay level. The microfacies analyses of the limestone beds highlighted their compositional and textural features and permitted the establishment of two main facies types: bio-extraclastic grainstone/packstone (MFT1) and bioclastic wackestone with Chapmanina (MFT2). The present micropaleontological association (benthic foraminifera, red algae, echinoids, bivalve fragments, bryozoans) is characteristic of a shallow-water depositional environment with frequent hydrodynamic oscillations from the middle-innermost parts of a carbonate ramp system. The presence of stylolites and numerous fissure sets in these facies highlights ongoing post-depositional processes, while the abundant extraclats (quartz grains) may confirm a proximal clastic source. Mineralogically, the main constituents of the non-carbonate units from the sedimentary succesion include quartz, calcite, muscovite, pyrite and chlorite, with occasional plagioclase feldspars and kaolinite. The clay fraction is dominated by muscovite and chlorite, with palygorskite and rectorite occurring in several samples. Secondary minerals formed through the exposure of the deposits to the cave environment are aragonite, iron hydroxides, gypsum and natrojarosite. In this context the presence of pyrite suggests reducing depositional conditions, while rectorite may indicate late diagenesis of the deposits. The observed microfacies variations between the lower and upper limestone beds, supported by the compositional features of the non-carbonate units, reveal a shallowing-up tendency for the whole sedimentary succession in the cave. Based on their paleontological and sedimentological features, the limestone beds from the cave are comparable to some of the Priabonian carbonates of the Transylvanian Basin and, more regionally, to many upper Eocene shallow-water ramp-type carbonates of the Neotethys.

Waste biogenic materials derived from seafood exploitation represent valuable resources of new compounds within the blue bioeconomy concept. Here, we describe the effectiveness of Raman technology implementation as an in-line tool for the demineralization process control of crustaceans or gastropods. Transparent chitin polymeric foils and calcium acetate by-products were obtained from three waste crustacean shells (C. sapidus, S. mantis, and M. squinado) using a slow, green chemical approach employing acetic acid. Progressive mineral dissolution and increasing of the Raman characteristic signal of chitin is shown in a time-dependent manner using NIR-Raman spectroscopy, while resonance Raman shows intact carotenoids in reacted shells after 2 weeks. Chitin foil products are species-specific, and the demineralization bath of the waste shell mixture can be effectively tracked by Raman tools for solvent control and decision making for the recovery of calcium acetate by-products. Comparatively obtained calcium acetate from Rapana venosa snail shells, the subject of Raman analyses, allowed assessing by-product identity, hydration status, purity, and suitability as recrystallized material for further use as a pharmaceutical compound derived from different crustaceans or gastropod species. Cross validation of the results was done using FT-IR, XRD, and SEM-EDX techniques. A hand-held flexible TacticID Raman system with 1064 nm excitation demonstrated its effectiveness as a rapid, in-line decision making tool during process control and revealed excellent reproducibility of the lab-based instrument signal, suitable for in situ evaluation of the demineralization status and solvent saturation control.